(Please read “What is a Domain Name?” first.)
Domain names are designed to bring order to Internet and make it easy for people to find the things they need.
Domain names are organized as a hierarchy with each level of that hierarchy separated by a “.” (dot). Each domain name has a Top Level Domain (TLD) which is the broadest level of the hierarchy. The TLD is listed on the far right. Examples are .COM, .ORG, or .NET. Individuals cannot own the top level domain.
The next level of the heirarchy is Second Level Domain (SLD). It is placed to the left of the TLD and separated by a dot. Anyone can register an SLD and use it exclusively as long as they continue to pay their annual registration fee. Examples of SLDs include Google, Yahoo, and NetFlint. When you put the Second Level Domain and the Top Level Domain together separated by a dot, you get a Domain Name.
Examples of Domain Names
There are many top level domains available today. Each TLD is meant for a certain type of website company, or use. For example, common TLDs include .COM to denote commercial enterprises, .ORG for organizations, or .NET for internet or network related websites.
For these and many TLDs, the stated purposes are mostly guidelines and not enforced. However, there are some TLDs that are strict in allowing only appropriate organizations to register them. These include .GOV for government and .EDU for education. Some country specific TLDs like Canada’s .CA require the registrant of a domain name to be a citizen or be doing business in the country to to be allowed to register the name.